10mph motorway driver given 7 day ban

Jonnycoupe said:
10-70 and 70-130 are both increases of 60mph.

130 - 70 will have more braking from the air and generally the driver will be more ready on the pedal than all the 70mph drivers eating sandwichs and watching the kids aswell.

130-70 the thing you might hit is still going 70mph.
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Yeah, but my understanding is that decreasing from 130mph to 70mph will require more energy and more braking distance than decreasing from 70mph to 10mph.

Kinetic energy increases with the square of the velocity (E = ½m·v^2) therefore the kinetic energy needed to be lost in reducing from 130mph to 70mph is considerably more than reducing from 70mph to 10mph and given that the maximum braking force available is going to be a constant, the braking distance will be considerably longer.

Am I confusing myself here or am I on the right tracks?
 
Scuzi said:
Yeah, but my understanding is that decreasing from 130mph to 70mph will require more energy and more braking distance than decreasing from 70mph to 10mph.

Kinetic energy increases with the square of the velocity (E = ½m·v^2) therefore the kinetic energy needed to be lost in reducing from 130mph to 70mph is considerably more than reducing from 70mph to 10mph and given that the maximum braking force available is going to be a constant, the braking distance will be considerably longer.
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Also consider downforce (if there is any on the particular car).

Main point is that the brakes will have to work harder as they have more energy to absorb, however they also have significantly more cooling air due to the higher vehicle speed and therefore disk rotation.

As said the wind resistance will aid the braking as it is providing a deceleration independant of the tyre's friction limits
 
I failed my test by not overtaking a tractor when i had the chance on one of those small roads NSL type and that area was the only straight bit where i had clear view. In my defense the road was going to bend and i wasn't sure if the car had the power to do it in time (obviously it did since the instructor said so).

On your 130-70 braking discussion, sure if you're doing 10mph like someone said before the slowest anything will be travelling is a 55mph lorry. If you drive under 10mph, you're almost a roadblock in a 2 or 3 lane motorway, forcing people to go around you or brake heavily as they're not expecting someone to drive so slow. Also EVERYTHING will be travelling faster than you, like the scenery is moving faster than you are.

If you're going 130 in a car fully capable of it, you're going to be the fastest driver on that part of the road, and you will be the one that needs to react to cars appearing almost stationary to you, but other drivers won't really have to react to you, plus they're probably expecting a fast car now and then on the motorway and know what to do ie stay in the same lane, or move over.

Some people maybe expecting ppl to drive at 50mph the slowest or something ridiculous like 140, but not under 10mph. I think they made the right decision with this one, and they need to hook her up with internet, staples sells expensive ink cartridges anyway.
 
Simon said:
Also consider downforce (if there is any on the particular car).

Main point is that the brakes will have to work harder as they have more energy to absorb, however they also have significantly more cooling air due to the higher vehicle speed and therefore disk rotation.

As said the wind resistance will aid the braking as it is providing a deceleration independant of the tyre's friction limits
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Brake cooling is hardly a factor if considering one emergency stop. If braking over a long period, yes, but in a one off stop the difference is going to be negligible.

Regardless of wind resistance, I am still of the opinion that braking from 130-70 will take considerably more distance than 70-10 would, especially on your average motorway Mondeo or Vectra.
 
Scuzi said:
Yeah, but my understanding is that decreasing from 130mph to 70mph will require more energy and more braking distance than decreasing from 70mph to 10mph.

Kinetic energy increases with the square of the velocity (E = ½m·v^2) therefore the kinetic energy needed to be lost in reducing from 130mph to 70mph is considerably more than reducing from 70mph to 10mph and given that the maximum braking force available is going to be a constant, the braking distance will be considerably longer.

Am I confusing myself here or am I on the right tracks?
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You are completely on the right tracks but apparently it's just as easy as:

130-70=60
70 - 10=60

Therefore breaking distance is the same.... Eh... NO!
 
She has effectively, iirc she's been required to retake her test, and I suspect it would have been passed on to the DVLA medical board who are a lot harsher and have many more options open to them in this sort of case than the magistrates.
Basically the court can only fine/ban her for a while in regards to the law for the offences committed (hence 7 days and retest), the DVLA medical board can suspend the license indefinitely until they are satisfied she is mentally and physically fit to drive (I believe it's fairly standard practice, if not a requirement for the court to pass on details of someone who they believe may be unfit to drive).
 
Muncher said:
Here's an interesting comment on the case by "Brake":mad:
Brake said:
This case sends out a very strange message to drivers. Mrs Cole was not breaking the speed limit or endangering anyone with her actions, yet she received a seven day ban, when we commonly see drivers caught travelling at 80 or 90mph get away with a fine and three points. While it is not common to encounter someone travelling at 10mph on a motorway, a competent driver should always be looking well ahead and predicting when they need to overtake a slower vehicle.
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Wow they are clearly quite insane. Did they actually read what they were defending. It wasn't just driving at 10mph it was swerving on and off the motorway into the paths of cars, into the path of a police car for goodness sake.

And even though you are looking ahead for obsticals even when you are presented with one its quite often that your avoidance is dangerous. You just don't tend to prosecute people who just crashed into the central reservation. You do prosecute people who effectively park on a motorway.

It neatly shows they have no interest in safety, just a rabid obsession with speed for reasons even they clearly don't understand.

People are stupid.

At least the magistrate dealt with it, I can't see that the dvla will let her have her license back after this. The most astounding thing is of course she was scared of motorways. I'd be scared stiff driving at 10mph! Sometimes 50mph can be a bit concerning! That's why I keep up with traffic. Nothing happens all that quickly because you are all doing roughly the same speed.
 
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Scuzi said:
Brake cooling is hardly a factor if considering one emergency stop. If braking over a long period, yes, but in a one off stop the difference is going to be negligible.

Regardless of wind resistance, I am still of the opinion that braking from 130-70 will take considerably more distance than 70-10 would, especially on your average motorway Mondeo or Vectra.
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Yeah you would expect the braking distance to be much bigger, simply cause your going faster.

However the car ahead at 70mph is also making the gap 'bigger'. You are not braking for a stationary object and so time rather than distance is the crux. The speed difference as mentioned is still 60mph.
 
Scuzi said:
Yeah, but my understanding is that decreasing from 130mph to 70mph will require more energy and more braking distance than decreasing from 70mph to 10mph.

Kinetic energy increases with the square of the velocity (E = ½m·v^2) therefore the kinetic energy needed to be lost in reducing from 130mph to 70mph is considerably more than reducing from 70mph to 10mph and given that the maximum braking force available is going to be a constant, the braking distance will be considerably longer.

Am I confusing myself here or am I on the right tracks?
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Indeed thats right, but thats based on kinetic energy and heat capacity of the brakes which Dogbreath has posted to assume ignorance to so the retardation of speed is the based solely on the tyre friction.

The braking distance will be longer but your end point of braking is still moving at a great rate as its 70mph. So if you were 200 metres behind a car and braked with the same force where you come to 10mph from a 10mph car will be around the same as coming to 70mph behind a 70mph car, your speeds will match and the distance stay the same. Now if you can assume you ignore brakes overheating the higher speed car actually has more force slowing it down as there is the added resistance of the air, although I guess tyre friction limits between the road and tyres will be slightly less as you have front end lift on most road cars at speed.
 
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Brake said:
This case sends out a very strange message to drivers. Mrs Cole was not breaking the speed limit or endangering anyone with her actions, yet she received a seven day ban, when we commonly see drivers caught travelling at 80 or 90mph get away with a fine and three points. While it is not common to encounter someone travelling at 10mph on a motorway, a competent driver should always be looking well ahead and predicting when they need to overtake a slower vehicle.
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I am sorry but what happens if an elderly driver is rapidly approaching a vehicle at 70mph... their reaction time when they realise they are driving at a near stationary object could be too late... as you wouldn't expect a car to be going THAT slow.

They would slam their brakes on causing cars to possibly go into the back of them and all hell breaks loose.

What happen if you are approaching the 10mph car and you can't change lanes due to traffic... you would again need to slam on the brakes... causing mayhem.

I am sorry but whoever made that statement was a total rubarb.
 
Booner! said:
I am sorry but what happens if an elderly driver is rapidly approaching a vehicle at 70mph... their reaction time when they realise they are driving at a near stationary object could be too late... as you wouldn't expect a car to be going THAT slow.
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Exactly someone doing 130 would be an idiot if they didnt expect a 70mph car up ahead.

However no one at 70 can expect a 10mph car, particular when its showing no brake lights, thats typically the first indication of potentially slower traffic when driving on a motorway in the normal commuter day dreaming mode.
 
Jonnycoupe said:
Exactly someone doing 130 would be an idiot if they didnt expect a 70mph car up ahead.

However no one at 70 can expect a 10mph car, particular when its showing no brake lights, thats typically the first indication of potentially slower traffic when driving on a motorway in the normal commuter day dreaming mode.
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Precisely, people can expect that behaviour on an average day to day journey and build up an expectation of how to adjust their driving. Driving at 10mph is a highly unlikely occasion to encounter and therefore nobody expects the car infront to be doing that speed.

Hence why there would be a 1-2 second slower response while your brain takes in the information and processes it to a reaction. This is where things can get messy.
 
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markyp23 said:
No she shouldn't.

If she becomes comfortable driving at a normal speed in the future then she has every right to her license.
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No. Nobody has a "right" to have a licence. I think they give licences out too easily - clearly this person has difficulties, she should rely on public transport.
 
LOL, i thought i was bad when i first went on the motorway after passing. I stayed at 60 in the left hand lane only overtaking a few very slow lorries, but would never of gone below 60. I think some form of motorway training should be mandatory IMO.
 
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